“I’m not proud of my first two books. Do me a favor,” writes Howard Stern, “and burn them.” Incredible as it may seem, Stern is a new man, and with “Howard Stern Comes Again,” he wants you to know it. The former bad boy of talk radio, the enfant terrible whose name was synonymous with leering chauvinism, has somehow morphed into an avuncular presence. Whether this presence can still capture the attention of the sprawling, fractured America of 2019 is an open question.

The fruits of Stern’s transformation are the 37 interviews in this book. The interviewees are a who’s who of show business, featuring musicians, comedians and actors: Lady Gaga, Tracy Morgan, Gwyneth Paltrow, Jay-Z, Billy Joel, Amy Poehler. With a few exceptions, the interviews take place in the past 10 years; there are only five that predate Stern’s move to satellite radio in 2006, when he was the terror of the airwaves and the toast of (some parts of) the town.

The resulting book is in equal measure disorienting, surprising and at times even oddly touching. For those who had intermittent exposure to Stern in his scabrous 1990s heyday but did not follow him to SiriusXM, it produces intense cognitive dissonance, like checking in with a snarling high school bully who has somehow become a gentle and supportive youth pastor.

For Stern 2.0, an on-air moment of emotional vulnerability from a guest “means they’re not threatened by me. They know they’re not going to be humiliated in some way.” Having non-stripper women on the show is “a priority,” because he wants his predominantly male audience “to see a woman like Gwyneth [Paltrow] as a human being and not just as some hot chick they watch in movies.”

Stern has always been smart and cunning, but his psychological acuity, deployed in service of this new warmth, occasionally takes his guests aback. “How do you know to ask that question?” wonders a perplexed Stephen Colbert, in response to a perceptive query about his relationship with his mother.

The answer, it turns out, is two decades of therapy. “I found myself changing my approach because I had experienced what it was like to have someone genuinely interested in my life,” Stern writes. “Therapy opened me up and enabled me to appreciate how fulfilling it was to be truly heard.”

Many of the interviews are outstanding. Stern’s decades in radio have unquestionably honed in him the near-mystical ability to get a guest talking freely, which is much, much harder than it looks. Even stripped of his voice – a velvety purr that remains one of the great radio voices – the interviews have palpable chemistry.

The interviews with comedians and talk show hosts, it seems to me, are especially fine. Collectively they serve as an oral history of contemporary comedy in America. They offer substantial insight into craft: Steve Martin talks about coming upon the revelation that if “the audience didn’t have . . . punchlines to laugh at, they would pick their own place to laugh. They would determine when to laugh. I wouldn’t be telling them” – a foundational breakthrough that shaped a generation of comedy writers.

Similarly, Bill Murray points out that the great “Saturday Night Live” casts “had what that first group had, which was they had writing ability,” but that in addition “they were more actors than stand-up comedians.” Stern has never been a stand-up comic, but he gets these people. He is profoundly in tune with the curious mixture of hostility and insecurity that propels so much comedy.

And what of Donald Trump? Stern is cagey about his most famous guest. Eleven times in the course of the book, he inserts excerpts from his interviews with Trump under the heading “And Now a Word From Our President.” None of them provide an epiphanic psychological insight into Trump – he’s the same self-absorbed blowhard, albeit a bit sharper and quicker.

There’s a whiff of the passive-aggressive to the tactic; the excerpts do not seem chosen to put Trump in either an especially good or bad light. Elsewhere Stern hedges, saying that “my political views are not good radio,” although he admits that he voted for Hillary Clinton and believes “she would have been a great president.”

“Howard Stern Comes Again” also raises extra-textual questions, both demographic and moral, that are mostly unanswerable. Will Stern’s traditional fan base of fraternity boys, cabdrivers and policemen show up for this book? What is his fan base, anyway, circa 2019? It can’t be the same people who made him a star in the 1990s, or can it?

More important, the book implicitly raises thorny questions about responsibility, agency and forgiveness, especially in the context of #MeToo and its fraught narratives of personal downfall and potential redemption. This is a man who did incalculable damage during his barbarian days – are we ready to forgive him? Is this change of heart legitimate? Today’s cultural landscape, bracingly, often calls upon each of us to practice a kind of moral calculus in affairs of public reputation. These matters are ineluctably complex and subjective, and in this, at least, “Howard Stern Comes Again” is perfectly of its time.